Lee Mold Not Filling Totally -- .361/38 S&W

[Agarbers]

I bought a mould from a seller on eBay that has Lee make .361 boolit moulds for the old.38 S&W cartridge. I am newer to boolit casting but none of my other Lee moulds have this issue after they are warm. The band doesn't seem to fill out all the way. It's as if air is trapped in the mold. I am only getting about 25% good casts. I do not have this issue with .358 or .452 Lee moulds.

Ideas?

[AlHunt]

IF that alloys casts well at that temperature in other molds, I'm going to suggest cleaning the mold. I have used a toothbrush and scouring powder (Bon Ami) with success when my bullets looked that way. I urge you to research that method before employing it on your own molds.

Or, that mold may want to run a little hotter.

I'll be interested in your cure.

[Bazoo]

It looks like oil contamination to me. Personally, what I do, is after the mould is up to nearly temperature but not quite all the way, I fill the cavities with lighter fluid. It won't burst into flames but do be careful. Fill the cavity full and it will boil like water. I never clean a mould with soap and water now, new or otherwise, since finding this technique.

Could be trapped air due to a combination of the bullet design and the technique you pour with but I'm guessing contamination.

[Conditor22]

when a mold doesn't fill out and it's up to temperature when other molds do with the same alloy My first impression is the mold is dirty, oil residue

scrub the cavities down with brake cleaner/acetone/carb cleaner then dish soap using a nylon brush (toothbrush, denture brush, ???

Preheat the mold on a hot plate with a piece of metal on it (sawblade or ?) up to 400° (hotplates are around $5 in thrift stores)

Lightly smoke the cavities with either a butane lighter or kitchen matches.

Depending on the alloy your using, the pot temperature should be around 680°-720° (lower for harder alloy and around 750° for pure lead)

with a clean mold preheated to 400° and clean alloy around 680°-720°, you should get good boolits right from the start.

You could try pressure casting (hold the mold tight to the spout on the pot after running a little lead through the spout so you have warm lead, fill the cavity the with the spout still open lower the mold so you get a puddle.

Make and model of the mold
what alloy and how hot the alloy is that your using
what pot you're using
and a picture of the cavities would be helpfull.

[Conditor22]

*** scrubbing the cavities/ face of the mold also helps clean out the vent lines. ***
usually, when the mold isn't venting properly the bases are rounded so I'm going with oil contamination.

[Agarbers]

Thanks. I am going to clean it and see what they look like tomorrow. I am about to go into a turkey coma right now...

[Drydock]

I have that mold, and it casts excellent bullets for my various .38 S&Ws. I also think you have oil contamination/plugged vents.

[country gent]

If cleaning dosnt work You can improve venting some with careful hand work
a Popsicle stick or small piece of flat stock. rubber cement a small piece of 600 grit paper to it, your making a small very fine hand file
When this is cured make 3-5 vey light passes down the top edge of each of the blocks at 45*, your cutting a vent line at the highest point. Go slow and easy as to big will allow finning

If this dosnt help with the grease groove then you need a small square and a scribe. Ti improve its venting
clamp the square onto the block so the blade is inline with the shoulder and with the scribe make 3-5 light passes in each corner cutting a light vent line
A die makers square is better than a square The die makers square can be set to 2*-3* up at the outside aiding air flow more.

You didnt say how you are pouring these bullets bottom pour, ladle. How big a stream is flowing. Or how big a sprue. Ideally you want a fast enoug fill the nose asnt started to solidify before the base is formed. You want a big enough sprue that stays molten so as the bullet cools the sprue fills in the void. Same with as the mould vents the sprue fills in voids.

The first I would try is a faster fill and biggest sprue you can pour. If your ladle casting over pour the mould. set blocks hanging over pot and pour a full ladle into cavity letting excess run back into pot.

If ladle casting with a lyman or rcbs ladle try pressure pouring the mould. Fill ladle and tip blocks on side fit nose snug into the blocks and tip up together to fill give a 3-5 count and form sprue. This can be done with a bottom pour pot also set the mould on spout snug and fill for a 3-5 count form sprue. this allows the pressure of the material to help push air out.

[Agarbers]

Cleaning did the trick. I didn't have any of the cleaners mentioned so I used denatured alcohol and a toothbrush. What a difference.

Make and model of the mold: LH 363 146
what alloy and how hot the alloy is that your using: range pick-up lead and 750 degrees.
what pot you're using: RCBS Pro-Melt II
and a picture of the cavities would be helpfull.[/QUOTE]

This is the one I bought: https://www.ebay.com/itm/Lee-Custom-...72.m2749.l2649

[Targa]

Yeh any oil/contamination makes for a frustrating casting experience. Glad you got it worked out.

[cwlongshot]

Very few problems found with fill out that wont be fixed by cleanliness, proper heat, good venting & some tin.

I buy brake clean by the case. Flush out molds while casting/ and just before.

Try things a lil hotter. Ya can always turn back down and frosty bullets aint a bad as some make them out ta be. ( Frost comes from too hot mold & or Alloy)

Venting are the little swirl cuts common on many molds today. Verticsl and horozontal on older molds. These allow air to bleed off providing better fillout.

The tin helps with fluidity of the alloy. Seldom any issues cause by its addition. But problems without enough.

Good luck

CW

[gwpercle]

Cleaning did the trick. I didn't have any of the cleaners mentioned so I used denatured alcohol and a toothbrush. What a difference.

Make and model of the mold: LH 363 146
what alloy and how hot the alloy is that your using: range pick-up lead and 750 degrees.
what pot you're using: RCBS Pro-Melt II
and a picture of the cavities would be helpfull.

This is the one I bought: https://www.ebay.com/itm/Lee-Custom-...72.m2749.l2649[/QUOTE]

Repeat the cleaning , toothbrush , alcohol (acetone woks best) before the next two or three casting sessions . Lee's new machines drives cutting oil deep into the pores of the metal . When you heat the mould more cutting oil comes to the surface .
It usually takes 3 casting sessions for all the oil to come out and for the new mould cavities to "season"... then you will have no more troubles ... theoretically !

When the new improved moulds came out I would scrub them , s , or better yet soak the blocks , in Acetone to pull out the oil . Heating to casting temperature , cast a few boolits and then set mould on top of pot and let slowly cool down ... called heat cycling ... three heat cycles got the mould clean and seasoned and seasoning does make a Huge difference in a moulds castability !

Be careful when using mould lube...it is so easy to contaminate the cavities... use just the slightest amount of lube.
Gary

[Conditor22]

I'm glad it worked out for you.

Oil really messes up mold cavities BUT IF you don't keep the sprue hinge screw, sprue plate, and alignment pins lubed you run into problems.

I use a needle tip bottle to apply a tiny drop of synthetic 2 stroke additive oil to the sprue screw, work the sprue several times, and wipe off any excess.

Apply synthetic 2 stroke additive oil to a q-tip and after cut the sprue and before you dump the boolits wipe the bottom of the sprue plate and the top of the mold. wait 15-20 seconds then wipe off the excess. Dump the boolits then using the same dampened Q-Tip carefully wipe the alignment pins and the alignment holes.

I try to do this a couple of times per pot full.

DON'T over tighten the sprue plate screw, the sprue plate (depending on its weight) should almost swing by itself for Lee 2X molds and swing freely for larger molds and molds with heavier sprue plates.

IF you see light between the outer edge of the sprue plate and the top of the mold your first instinct is to tighten the screw. --- DON"T!! loosen it a little, that will bring the high side down.

IF the base of your boolits don't fill out it's either because you didn't clear the nozzle on the pot before the cast getting rid of any cooler lead into the catch container under the nozzle or the sprue plate is too cool. I confirmed this theory by grabbing a cold mold, warming up the sprue plate with a propane torch, and pouring boolits. the bases came out great.

This is what happens IF you overtighten or don't keep the sprue screw lubed


when I was given this mold the sprue plate was sticking up in the air. I removed the sprue plate stop pin put a coarse piece of wet-dry sandpaper on a piece of glass and sanded the mold top keeping it flat until I got a smooth surface again. I did the same with the bottom of the sprue plate until sanding marks covered the entire bottom of the plate. Repeated the process with a finer sandpaper, put the mold back together and Bingo it cast nice (very slightly lighter) boolits that shot great.

my 2¢